| /* crypto/dsa/dsa_gen.c */ |
| /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) |
| * All rights reserved. |
| * |
| * This package is an SSL implementation written |
| * by Eric Young (eay@cryptsoft.com). |
| * The implementation was written so as to conform with Netscapes SSL. |
| * |
| * This library is free for commercial and non-commercial use as long as |
| * the following conditions are aheared to. The following conditions |
| * apply to all code found in this distribution, be it the RC4, RSA, |
| * lhash, DES, etc., code; not just the SSL code. The SSL documentation |
| * included with this distribution is covered by the same copyright terms |
| * except that the holder is Tim Hudson (tjh@cryptsoft.com). |
| * |
| * Copyright remains Eric Young's, and as such any Copyright notices in |
| * the code are not to be removed. |
| * If this package is used in a product, Eric Young should be given attribution |
| * as the author of the parts of the library used. |
| * This can be in the form of a textual message at program startup or |
| * in documentation (online or textual) provided with the package. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. All advertising materials mentioning features or use of this software |
| * must display the following acknowledgement: |
| * "This product includes cryptographic software written by |
| * Eric Young (eay@cryptsoft.com)" |
| * The word 'cryptographic' can be left out if the rouines from the library |
| * being used are not cryptographic related :-). |
| * 4. If you include any Windows specific code (or a derivative thereof) from |
| * the apps directory (application code) you must include an acknowledgement: |
| * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" |
| * |
| * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * |
| * The licence and distribution terms for any publically available version or |
| * derivative of this code cannot be changed. i.e. this code cannot simply be |
| * copied and put under another distribution licence |
| * [including the GNU Public Licence.] |
| */ |
| |
| /* |
| * Parameter generation follows the updated Appendix 2.2 for FIPS PUB 186, |
| * also Appendix 2.2 of FIPS PUB 186-1 (i.e. use SHA as defined in FIPS PUB |
| * 180-1) |
| */ |
| #define xxxHASH EVP_sha1() |
| |
| #include <openssl/opensslconf.h> /* To see if OPENSSL_NO_SHA is defined */ |
| |
| #include <stdio.h> |
| #include "cryptlib.h" |
| #include <openssl/evp.h> |
| #include <openssl/bn.h> |
| #include <openssl/rand.h> |
| #include <openssl/sha.h> |
| |
| #include "dsa_locl.h" |
| |
| int DSA_generate_parameters_ex(DSA *ret, int bits, |
| const unsigned char *seed_in, int seed_len, |
| int *counter_ret, unsigned long *h_ret, |
| BN_GENCB *cb) |
| { |
| if (ret->meth->dsa_paramgen) |
| return ret->meth->dsa_paramgen(ret, bits, seed_in, seed_len, |
| counter_ret, h_ret, cb); |
| else { |
| const EVP_MD *evpmd; |
| size_t qbits = bits >= 2048 ? 256 : 160; |
| |
| if (bits >= 2048) { |
| qbits = 256; |
| evpmd = EVP_sha256(); |
| } else { |
| qbits = 160; |
| evpmd = EVP_sha1(); |
| } |
| |
| return dsa_builtin_paramgen(ret, bits, qbits, evpmd, |
| seed_in, seed_len, NULL, counter_ret, |
| h_ret, cb); |
| } |
| } |
| |
| int dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits, |
| const EVP_MD *evpmd, const unsigned char *seed_in, |
| size_t seed_len, unsigned char *seed_out, |
| int *counter_ret, unsigned long *h_ret, BN_GENCB *cb) |
| { |
| int ok = 0; |
| unsigned char seed[SHA256_DIGEST_LENGTH]; |
| unsigned char md[SHA256_DIGEST_LENGTH]; |
| unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH]; |
| BIGNUM *r0, *W, *X, *c, *test; |
| BIGNUM *g = NULL, *q = NULL, *p = NULL; |
| BN_MONT_CTX *mont = NULL; |
| int i, k, n = 0, m = 0, qsize = qbits >> 3; |
| int counter = 0; |
| int r = 0; |
| BN_CTX *ctx = NULL; |
| unsigned int h = 2; |
| |
| if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH && |
| qsize != SHA256_DIGEST_LENGTH) |
| /* invalid q size */ |
| return 0; |
| |
| if (evpmd == NULL) |
| /* use SHA1 as default */ |
| evpmd = EVP_sha1(); |
| |
| if (bits < 512) |
| bits = 512; |
| |
| bits = (bits + 63) / 64 * 64; |
| |
| /* |
| * NB: seed_len == 0 is special case: copy generated seed to seed_in if |
| * it is not NULL. |
| */ |
| if (seed_len && (seed_len < (size_t)qsize)) |
| seed_in = NULL; /* seed buffer too small -- ignore */ |
| if (seed_len > (size_t)qsize) |
| seed_len = qsize; /* App. 2.2 of FIPS PUB 186 allows larger |
| * SEED, but our internal buffers are |
| * restricted to 160 bits */ |
| if (seed_in != NULL) |
| memcpy(seed, seed_in, seed_len); |
| |
| if ((ctx = BN_CTX_new()) == NULL) |
| goto err; |
| |
| if ((mont = BN_MONT_CTX_new()) == NULL) |
| goto err; |
| |
| BN_CTX_start(ctx); |
| r0 = BN_CTX_get(ctx); |
| g = BN_CTX_get(ctx); |
| W = BN_CTX_get(ctx); |
| q = BN_CTX_get(ctx); |
| X = BN_CTX_get(ctx); |
| c = BN_CTX_get(ctx); |
| p = BN_CTX_get(ctx); |
| test = BN_CTX_get(ctx); |
| |
| if (!BN_lshift(test, BN_value_one(), bits - 1)) |
| goto err; |
| |
| for (;;) { |
| for (;;) { /* find q */ |
| int seed_is_random; |
| |
| /* step 1 */ |
| if (!BN_GENCB_call(cb, 0, m++)) |
| goto err; |
| |
| if (!seed_len) { |
| if (RAND_bytes(seed, qsize) <= 0) |
| goto err; |
| seed_is_random = 1; |
| } else { |
| seed_is_random = 0; |
| seed_len = 0; /* use random seed if 'seed_in' turns out to |
| * be bad */ |
| } |
| memcpy(buf, seed, qsize); |
| memcpy(buf2, seed, qsize); |
| /* precompute "SEED + 1" for step 7: */ |
| for (i = qsize - 1; i >= 0; i--) { |
| buf[i]++; |
| if (buf[i] != 0) |
| break; |
| } |
| |
| /* step 2 */ |
| if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL)) |
| goto err; |
| if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL)) |
| goto err; |
| for (i = 0; i < qsize; i++) |
| md[i] ^= buf2[i]; |
| |
| /* step 3 */ |
| md[0] |= 0x80; |
| md[qsize - 1] |= 0x01; |
| if (!BN_bin2bn(md, qsize, q)) |
| goto err; |
| |
| /* step 4 */ |
| r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, |
| seed_is_random, cb); |
| if (r > 0) |
| break; |
| if (r != 0) |
| goto err; |
| |
| /* do a callback call */ |
| /* step 5 */ |
| } |
| |
| if (!BN_GENCB_call(cb, 2, 0)) |
| goto err; |
| if (!BN_GENCB_call(cb, 3, 0)) |
| goto err; |
| |
| /* step 6 */ |
| counter = 0; |
| /* "offset = 2" */ |
| |
| n = (bits - 1) / 160; |
| |
| for (;;) { |
| if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) |
| goto err; |
| |
| /* step 7 */ |
| BN_zero(W); |
| /* now 'buf' contains "SEED + offset - 1" */ |
| for (k = 0; k <= n; k++) { |
| /* |
| * obtain "SEED + offset + k" by incrementing: |
| */ |
| for (i = qsize - 1; i >= 0; i--) { |
| buf[i]++; |
| if (buf[i] != 0) |
| break; |
| } |
| |
| if (!EVP_Digest(buf, qsize, md, NULL, evpmd, NULL)) |
| goto err; |
| |
| /* step 8 */ |
| if (!BN_bin2bn(md, qsize, r0)) |
| goto err; |
| if (!BN_lshift(r0, r0, (qsize << 3) * k)) |
| goto err; |
| if (!BN_add(W, W, r0)) |
| goto err; |
| } |
| |
| /* more of step 8 */ |
| if (!BN_mask_bits(W, bits - 1)) |
| goto err; |
| if (!BN_copy(X, W)) |
| goto err; |
| if (!BN_add(X, X, test)) |
| goto err; |
| |
| /* step 9 */ |
| if (!BN_lshift1(r0, q)) |
| goto err; |
| if (!BN_mod(c, X, r0, ctx)) |
| goto err; |
| if (!BN_sub(r0, c, BN_value_one())) |
| goto err; |
| if (!BN_sub(p, X, r0)) |
| goto err; |
| |
| /* step 10 */ |
| if (BN_cmp(p, test) >= 0) { |
| /* step 11 */ |
| r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb); |
| if (r > 0) |
| goto end; /* found it */ |
| if (r != 0) |
| goto err; |
| } |
| |
| /* step 13 */ |
| counter++; |
| /* "offset = offset + n + 1" */ |
| |
| /* step 14 */ |
| if (counter >= 4096) |
| break; |
| } |
| } |
| end: |
| if (!BN_GENCB_call(cb, 2, 1)) |
| goto err; |
| |
| /* We now need to generate g */ |
| /* Set r0=(p-1)/q */ |
| if (!BN_sub(test, p, BN_value_one())) |
| goto err; |
| if (!BN_div(r0, NULL, test, q, ctx)) |
| goto err; |
| |
| if (!BN_set_word(test, h)) |
| goto err; |
| if (!BN_MONT_CTX_set(mont, p, ctx)) |
| goto err; |
| |
| for (;;) { |
| /* g=test^r0%p */ |
| if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont)) |
| goto err; |
| if (!BN_is_one(g)) |
| break; |
| if (!BN_add(test, test, BN_value_one())) |
| goto err; |
| h++; |
| } |
| |
| if (!BN_GENCB_call(cb, 3, 1)) |
| goto err; |
| |
| ok = 1; |
| err: |
| if (ok) { |
| BN_free(ret->p); |
| BN_free(ret->q); |
| BN_free(ret->g); |
| ret->p = BN_dup(p); |
| ret->q = BN_dup(q); |
| ret->g = BN_dup(g); |
| if (ret->p == NULL || ret->q == NULL || ret->g == NULL) { |
| ok = 0; |
| goto err; |
| } |
| if (counter_ret != NULL) |
| *counter_ret = counter; |
| if (h_ret != NULL) |
| *h_ret = h; |
| if (seed_out) |
| memcpy(seed_out, seed, qsize); |
| } |
| if (ctx) |
| BN_CTX_end(ctx); |
| BN_CTX_free(ctx); |
| BN_MONT_CTX_free(mont); |
| return ok; |
| } |
| |
| /* |
| * This is a parameter generation algorithm for the DSA2 algorithm as |
| * described in FIPS 186-3. |
| */ |
| |
| int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N, |
| const EVP_MD *evpmd, const unsigned char *seed_in, |
| size_t seed_len, int idx, unsigned char *seed_out, |
| int *counter_ret, unsigned long *h_ret, |
| BN_GENCB *cb) |
| { |
| int ok = -1; |
| unsigned char *seed = NULL, *seed_tmp = NULL; |
| unsigned char md[EVP_MAX_MD_SIZE]; |
| int mdsize; |
| BIGNUM *r0, *W, *X, *c, *test; |
| BIGNUM *g = NULL, *q = NULL, *p = NULL; |
| BN_MONT_CTX *mont = NULL; |
| int i, k, n = 0, m = 0, qsize = N >> 3; |
| int counter = 0; |
| int r = 0; |
| BN_CTX *ctx = NULL; |
| EVP_MD_CTX mctx; |
| unsigned int h = 2; |
| |
| EVP_MD_CTX_init(&mctx); |
| |
| if (evpmd == NULL) { |
| if (N == 160) |
| evpmd = EVP_sha1(); |
| else if (N == 224) |
| evpmd = EVP_sha224(); |
| else |
| evpmd = EVP_sha256(); |
| } |
| |
| mdsize = M_EVP_MD_size(evpmd); |
| /* If unverificable g generation only don't need seed */ |
| if (!ret->p || !ret->q || idx >= 0) { |
| if (seed_len == 0) |
| seed_len = mdsize; |
| |
| seed = OPENSSL_malloc(seed_len); |
| |
| if (seed_out) |
| seed_tmp = seed_out; |
| else |
| seed_tmp = OPENSSL_malloc(seed_len); |
| |
| if (!seed || !seed_tmp) |
| goto err; |
| |
| if (seed_in) |
| memcpy(seed, seed_in, seed_len); |
| |
| } |
| |
| if ((ctx = BN_CTX_new()) == NULL) |
| goto err; |
| |
| if ((mont = BN_MONT_CTX_new()) == NULL) |
| goto err; |
| |
| BN_CTX_start(ctx); |
| r0 = BN_CTX_get(ctx); |
| g = BN_CTX_get(ctx); |
| W = BN_CTX_get(ctx); |
| X = BN_CTX_get(ctx); |
| c = BN_CTX_get(ctx); |
| test = BN_CTX_get(ctx); |
| |
| /* if p, q already supplied generate g only */ |
| if (ret->p && ret->q) { |
| p = ret->p; |
| q = ret->q; |
| if (idx >= 0) |
| memcpy(seed_tmp, seed, seed_len); |
| goto g_only; |
| } else { |
| p = BN_CTX_get(ctx); |
| q = BN_CTX_get(ctx); |
| } |
| |
| if (!BN_lshift(test, BN_value_one(), L - 1)) |
| goto err; |
| for (;;) { |
| for (;;) { /* find q */ |
| unsigned char *pmd; |
| /* step 1 */ |
| if (!BN_GENCB_call(cb, 0, m++)) |
| goto err; |
| |
| if (!seed_in) { |
| if (RAND_bytes(seed, seed_len) <= 0) |
| goto err; |
| } |
| /* step 2 */ |
| if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL)) |
| goto err; |
| /* Take least significant bits of md */ |
| if (mdsize > qsize) |
| pmd = md + mdsize - qsize; |
| else |
| pmd = md; |
| |
| if (mdsize < qsize) |
| memset(md + mdsize, 0, qsize - mdsize); |
| |
| /* step 3 */ |
| pmd[0] |= 0x80; |
| pmd[qsize - 1] |= 0x01; |
| if (!BN_bin2bn(pmd, qsize, q)) |
| goto err; |
| |
| /* step 4 */ |
| r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx, |
| seed_in ? 1 : 0, cb); |
| if (r > 0) |
| break; |
| if (r != 0) |
| goto err; |
| /* Provided seed didn't produce a prime: error */ |
| if (seed_in) { |
| ok = 0; |
| DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME); |
| goto err; |
| } |
| |
| /* do a callback call */ |
| /* step 5 */ |
| } |
| /* Copy seed to seed_out before we mess with it */ |
| if (seed_out) |
| memcpy(seed_out, seed, seed_len); |
| |
| if (!BN_GENCB_call(cb, 2, 0)) |
| goto err; |
| if (!BN_GENCB_call(cb, 3, 0)) |
| goto err; |
| |
| /* step 6 */ |
| counter = 0; |
| /* "offset = 1" */ |
| |
| n = (L - 1) / (mdsize << 3); |
| |
| for (;;) { |
| if ((counter != 0) && !BN_GENCB_call(cb, 0, counter)) |
| goto err; |
| |
| /* step 7 */ |
| BN_zero(W); |
| /* now 'buf' contains "SEED + offset - 1" */ |
| for (k = 0; k <= n; k++) { |
| /* |
| * obtain "SEED + offset + k" by incrementing: |
| */ |
| for (i = seed_len - 1; i >= 0; i--) { |
| seed[i]++; |
| if (seed[i] != 0) |
| break; |
| } |
| |
| if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL)) |
| goto err; |
| |
| /* step 8 */ |
| if (!BN_bin2bn(md, mdsize, r0)) |
| goto err; |
| if (!BN_lshift(r0, r0, (mdsize << 3) * k)) |
| goto err; |
| if (!BN_add(W, W, r0)) |
| goto err; |
| } |
| |
| /* more of step 8 */ |
| if (!BN_mask_bits(W, L - 1)) |
| goto err; |
| if (!BN_copy(X, W)) |
| goto err; |
| if (!BN_add(X, X, test)) |
| goto err; |
| |
| /* step 9 */ |
| if (!BN_lshift1(r0, q)) |
| goto err; |
| if (!BN_mod(c, X, r0, ctx)) |
| goto err; |
| if (!BN_sub(r0, c, BN_value_one())) |
| goto err; |
| if (!BN_sub(p, X, r0)) |
| goto err; |
| |
| /* step 10 */ |
| if (BN_cmp(p, test) >= 0) { |
| /* step 11 */ |
| r = BN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1, cb); |
| if (r > 0) |
| goto end; /* found it */ |
| if (r != 0) |
| goto err; |
| } |
| |
| /* step 13 */ |
| counter++; |
| /* "offset = offset + n + 1" */ |
| |
| /* step 14 */ |
| if (counter >= (int)(4 * L)) |
| break; |
| } |
| if (seed_in) { |
| ok = 0; |
| DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_INVALID_PARAMETERS); |
| goto err; |
| } |
| } |
| end: |
| if (!BN_GENCB_call(cb, 2, 1)) |
| goto err; |
| |
| g_only: |
| |
| /* We now need to generate g */ |
| /* Set r0=(p-1)/q */ |
| if (!BN_sub(test, p, BN_value_one())) |
| goto err; |
| if (!BN_div(r0, NULL, test, q, ctx)) |
| goto err; |
| |
| if (idx < 0) { |
| if (!BN_set_word(test, h)) |
| goto err; |
| } else |
| h = 1; |
| if (!BN_MONT_CTX_set(mont, p, ctx)) |
| goto err; |
| |
| for (;;) { |
| static const unsigned char ggen[4] = { 0x67, 0x67, 0x65, 0x6e }; |
| if (idx >= 0) { |
| md[0] = idx & 0xff; |
| md[1] = (h >> 8) & 0xff; |
| md[2] = h & 0xff; |
| if (!EVP_DigestInit_ex(&mctx, evpmd, NULL)) |
| goto err; |
| if (!EVP_DigestUpdate(&mctx, seed_tmp, seed_len)) |
| goto err; |
| if (!EVP_DigestUpdate(&mctx, ggen, sizeof(ggen))) |
| goto err; |
| if (!EVP_DigestUpdate(&mctx, md, 3)) |
| goto err; |
| if (!EVP_DigestFinal_ex(&mctx, md, NULL)) |
| goto err; |
| if (!BN_bin2bn(md, mdsize, test)) |
| goto err; |
| } |
| /* g=test^r0%p */ |
| if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont)) |
| goto err; |
| if (!BN_is_one(g)) |
| break; |
| if (idx < 0 && !BN_add(test, test, BN_value_one())) |
| goto err; |
| h++; |
| if (idx >= 0 && h > 0xffff) |
| goto err; |
| } |
| |
| if (!BN_GENCB_call(cb, 3, 1)) |
| goto err; |
| |
| ok = 1; |
| err: |
| if (ok == 1) { |
| if (p != ret->p) { |
| BN_free(ret->p); |
| ret->p = BN_dup(p); |
| } |
| if (q != ret->q) { |
| BN_free(ret->q); |
| ret->q = BN_dup(q); |
| } |
| BN_free(ret->g); |
| ret->g = BN_dup(g); |
| if (ret->p == NULL || ret->q == NULL || ret->g == NULL) { |
| ok = -1; |
| goto err; |
| } |
| if (counter_ret != NULL) |
| *counter_ret = counter; |
| if (h_ret != NULL) |
| *h_ret = h; |
| } |
| OPENSSL_free(seed); |
| if (seed_out != seed_tmp) |
| OPENSSL_free(seed_tmp); |
| if (ctx) |
| BN_CTX_end(ctx); |
| BN_CTX_free(ctx); |
| BN_MONT_CTX_free(mont); |
| EVP_MD_CTX_cleanup(&mctx); |
| return ok; |
| } |
| |
| int dsa_paramgen_check_g(DSA *dsa) |
| { |
| BN_CTX *ctx; |
| BIGNUM *tmp; |
| BN_MONT_CTX *mont = NULL; |
| int rv = -1; |
| ctx = BN_CTX_new(); |
| if (!ctx) |
| return -1; |
| BN_CTX_start(ctx); |
| if (BN_cmp(dsa->g, BN_value_one()) <= 0) |
| return 0; |
| if (BN_cmp(dsa->g, dsa->p) >= 0) |
| return 0; |
| tmp = BN_CTX_get(ctx); |
| if (!tmp) |
| goto err; |
| if ((mont = BN_MONT_CTX_new()) == NULL) |
| goto err; |
| if (!BN_MONT_CTX_set(mont, dsa->p, ctx)) |
| goto err; |
| /* Work out g^q mod p */ |
| if (!BN_mod_exp_mont(tmp, dsa->g, dsa->q, dsa->p, ctx, mont)) |
| goto err; |
| if (!BN_cmp(tmp, BN_value_one())) |
| rv = 1; |
| else |
| rv = 0; |
| err: |
| BN_CTX_end(ctx); |
| BN_MONT_CTX_free(mont); |
| BN_CTX_free(ctx); |
| return rv; |
| |
| } |
